"It's a toe in the water," Ms. Anderson said. That toe is likely to cause a splash among real-estate brokers, however, because Mr. Diller has long been seen as a major potential rival. Just as services like Expedia hammered local travel agents, online real-estate operators could eat into the revenue of local real-estate brokers, though selling homes is much more complicated than selling airline tickets.Not a surprise, the referral business is not very big, at least by Diller standards.IAC is active in residential real-estate through its LendingTree.com and RealEstate.com sites, which offer to find an agent for buyers or sellers. The brokerage firms where those agents work agree to pay about 30% of the commission to those IAC units, which share the money with the consumer, often in the form of a Home Depot or American Express gift card. IAC also offers such rebates through affinity programs with airlines and Costco Wholesale Corp.
